In general, a color reversal photographic light-sensitive material has a narrow exposure latitude range. It is therefore difficult to select exposure which provides optimum image over many different scenes. In a color reversal light-sensitive material, treatment time is often altered to provide desired images. In photographing scenes requiring high shutter speed or scenes short of light necessary for exposure by such a color reversal photographic light-sensitive material, it is usual that the sensitivity adjustment is accomplished by prolonging the development time to make up for the shortage of sensitivity. Such a sensitivity adjustment is generally called "sensitization processing". In such a color reversal photographic light-sensitive material, sensitization processing is accomplished by prolonging first development (black-and-white negative development).
In general, the treatment of a color reversal photographic light-sensitive material is conducted in the following steps:
Black-and-white development (first development).fwdarw.stopping.fwdarw.rinsing.fwdarw.reversal.fwdarw.rinsing .fwdarw.color development.fwdarw.stopping.fwdarw.rinsing.fwdarw.adjustment bath.fwdarw.rinsing.fwdarw.bleaching.fwdarw.rinsing.fwdarw.fixation.fwdarw .rinsing.fwdarw.drying.
The first developing agent contains a silver halide solvent such as KSCN to cause a solution physical development which provides an effect of promoting the black-and-white development. Accordingly, in the first development of color reversal treatment, a so-called chemical development and a solution physical development take place at the same time. In other words, a solution physical development of nucleus of developed silver grains which have been exposed to form a latent image, or had a previously fogged nucleus and started to undergo chemical development, or colloidal silver contained in a yellow filter layer, takes place at the same time. Accordingly, in order to provide a color reversal photographic light-sensitive material adapted for sensitized development, it has been needed to design a silver halide emulsion which enables the controlling of not only the rate at which the chemical development proceeds but also the rate at which the solution physical development proceeds, depending on the development time.
In general, a silver halide color reversal photographic light-sensitive material comprises silver halide grains containing silver iodide. It is well known that in such silver halide grains the development speed can be controlled by the total silver iodide content thereof. For example, it is described in the Journal of Photographic Science, Vol. 24, pp. 198-202 (1976) that when silver halide grains having a high silver iodide content are used, the change in the amount of developed silver with development time can be increased even in a process in which only chemical development takes place or in a process in which a solution physical development is involved. However, when silver halide grains having a high silver iodide content are used, it is usual that the initial development is delayed, resulting in a drastic decrease in sensitivity upon shortening of the development time. It is also usual that the delayed development results in low contrast, making it impossible to provide desired images. Furthermore, silver halide grains having a very high silver iodide content remarkably inhibits the rate at which a solution physical development proceeds. Accordingly, the use of such silver halide grains may cause a rise in the minimum density (stain) or a reduction in contrast. Therefore, in a color reversal light-sensitive material, it is difficult to increase the sensitivity by the sensitization processing while obtaining desired images by increasing the total content of silver iodide in the silver halide grains.
In recent years, on the other hand, techniques for the preparation of silver halide grains have made progress, and attempts have been made to create a specific silver iodide distribution inside the grains of silver halide in order to control the development speed thereof. For example, it is described in The International East-West Symposium on the Factors Influencing Photographic Sensitivity, (B-27, 1984) that a so-called double structured grains in which silver iodide is present more in the inner phase (core) thereof and less on a phase (shell) including the surface thereof is advantageous from the viewpoint of sensitivity and development activity. It is also reported in the above described issue of Journal of Photographic Science that grains comprising a phase having a silver iodide content inside thereof undergo a chemical development at a higher speed than grains comprising a surface phase having a high silver iodide content.
However, such a structure is aimed at improving the development activity of the grain surface, accelerating the relatively early chemical development, while preventing the chemical development from processing into the grain beyond a predetermined limit during the last stage of the development. Accordingly, such a structure is essentially against the adaptability to the sensitization processing which requires an increase in the sensitivity change during the last stage of the development. Furthermore, in a color reversal treatment involving a vigorous solution physical development, grains containing an inner (core) phase having a high silver iodide content are difficult to dissolve in the developing agent after reaching the phase. This prevents the solution physical development from proceeding. This also results in a reduction in sensitization by high speed development, reduction in contrast, and a rise in minimum density (stain). Thus, a grain structure fully satisfying adaptability to high speed development of a color reversal photographic light-sensitive material has not yet been found.